The OpenROV could potentially be very useful for Florida cave explorers.
To find new caves we normally go hiking in the woods and jump in whatever water-filled sink holes we find, to see if there is a cave entrance at the bottom. But these sink holes often have a layer of very dark water on the surface, but a few feet down they can be crystal clear. But it can also be just a mud hole. Sending down a small ROV like this could save a lot of time and energy for us. Also, there are often Alligators and snakes in these sink holes, so sending an ROV would also reduce some of the potential risk associated with these wildlife encounters.
To measure water visibility you could mount two small laser pointers (one of each side of the ROV) that converge at a set distance in front of the camera (set at the minimum distance/visibility you are willing to dive in). If you see the point where the laser beams converge you know that the visibility is good enough to send divers down. :)
If anyone has a low-cost DIY kit for a tiny sonar-array one could also make the ROV into a digital 3D wall-mapper..
Great project so far!